Now ISPs will be required to deliver details of those customers from its own records, and will have to send a letter warning customers to use legal alternatives to those sites.

The code will cover the six top ISPs, which have 93% of the retail broadband market - BT, Everything Everywhere, O2, Sky, TalkTalk Group and Virgin Media.

After three warnings in a year a customer will be 'blacklisted', and could face civil claims under the Copyright, Designs and Patents Act via a court order:

If a customer receives three letters or more within a 12-month period, anonymous information may be provided on request to copyright owners showing them which infringement reports are linked to that customer's account. The copyright owner may then seek a court order requiring the ISP to reveal the identity of the customer, with a view to taking legal action for infringement under the Copyright Designs and Patent Act 1988.

Among the changes to the measures, customers will have 20 days to appeal against any accusations - after paying a £20 fee to do so.

Legitimate grounds for appeal, as mentioned in the original act, including someone else using their WiFi network despite steps taken to prevent access.

Ofcom said:

Customers would have the right to challenge any allegation of infringement through an independent appeals body. Ofcom will appoint this body and require it to establish transparent, accessible appeal procedures. Copyright owners will need Ofcom approval of their procedures for gathering evidence of infringement before they can be used under the scheme.

Claudio Pollack, Ofcom's Consumer Group Director, said: "These measures are designed to foster investment and innovation in the UK's creative industries, while ensuring internet users are treated fairly and given help to access lawful content.

"Ofcom will oversee a fair appeals process, and also ensure that rights holders' investigations under the code are rigorous and transparent."

The moves were criticised by some, who said that by imposing an appeals fee the government was assuming customers were guilty before guilt was proven.

Jim Killock of the Open Rights Group said:

"Digital revenues are going up, the music and film industry are moving in the right direction, yet this cumbersome policy is still lumbering forward.

"Ofcom are being asked to put lipstick on a pig with this code.

"The appeals are a joke. The Government has decided that 'I didn't do it' is not a defence. Some people will almost certainly end up in court having done nothing wrong."

Mike O’Connor, chief executive of Consumer Focus, added:

"Copyright infringement is not to be condoned, but people who are innocent should not have to pay a fee to challenge accusations.

"Consumers are innocent until proven guilty. Twenty pounds may sound like a small sum, but it could deter those living on low-incomes from challenging unfair allegations. Ultimately consumers could be subject to “technical measures”, including being cut off from the internet, and the ability to appeal is therefore critical to ensure consumers who have done nothing wrong are not deprived of essential internet access further down the line."